Sunday, April 22, 2012

Left-Side Bike Lane on Commonwealth Avenue, Back Bay, Including Underpass, but not Including Transition from Right to Left

By, Isaac Almy

Background

Commonwealth Avenue is two way street in Boston with each
direction separated with a vertical park in the middle.

Commonwealth Avenue Highlighted in Blue

In 2010 a bike lane was added to the left side of the
street. Before the bike lane was added cyclists rode on the right side of the
street next to parked cars. This put the cyclist at risk of getting "doored"
as a person got out of their vehicle.

Commonwealth Avenue Before Added Bike Lanes (google street view)

Added
Bike Lanes

Bike
lanes were added in each direction on the left side. At the start of the bike
lanes markings are made to tell the cyclist to ride on the left.

Start of Left Side Bike Lanes

You can see from the picture that sometimes cars will be
parked where the markings are.

Left Side Bike Lane on Commonwealth Avenue

The
bike lane is to the left of the cars and to the right of the park. In heavy
traffic it is easy for a bike to travel faster than a car. The bike lane isn't
next to any parked cars and so there is no risk of dooring. The bike lanes are about 4ft wide. There is enough space for one cyclist but not for bikes going side by side. Cyclists can safely travel in the lane uninterrupted by cars.

Boston Cab Driver Blocking the Bike Lane

Unless a Boston cab driver blocks the lane. Most cars will
stay in their lane and keep the bike lane clear.

Bike Box

On cross streets where a bike can make a right turn. A bike
box is added at the intersection. You can also see there are green markings leading up to the intersection. This makes more aware of cyclists.

Cars Stopping Before the Bike Box

At the intersection cars will stop before the bike box,
which allows bikes to safely cross the street in front of them.

Boston Cab Driver in the Bike Box

Unless a Boston cab driver gets in your way.

Underpass

At the intersection of Massachusetts avenue and Commonwealth
Avenue an underpass was built to allow Commonwealth to go underneath Massachusetts
Avenue. The bike lane stays on the left side and a buffer zone is created
between the cars and the bikes. Cars going under the underpass are going 30mph or more and the buffer zone protects the cyclists from the higher speed vehicles.

Bike Lane Before the Underpass with a Buffer Zone

The buffer area is about 2ft in width. The cars are a safe
distance away from the cyclist. Going underneath the underpass is a breeze and
merging back into traffic is simple because the bike lane continues on the
other side.

Conclusion

The bike lanes on commonwealth avenue are a great addition
to Boston's bicycle network. The bike lane on the left side of the street
prevents dooring. The buffered bike lanes for the underpass add some space for
the cyclist and has little effect on cars. When cars are making a left turn off of Commonwealth they need to pay attention to cyclists going through the intersection. Motorists aren't used to looking for cyclists as they turn left. The cyclist needs to be aware of any turning cars and make adjustments in speed as needed.